Win_Strain calculates the strain between two sets of unit-cell parameters. This is essential for interpreting changes in unit-cell parameters with changes in temperature, pressure or composition, or for calculating the components of the spontaneous strain arising from a phase transition. When the components of the strain tensor are normalised by the temperature or pressure change, the thermal expansion and compressibility tensors are obtained. For crystals of monoclinic or triclinic symmetry the orientation of the principal axes of strain with respect to both the Cartesian axial system and the crystallographic axes is also calculated. This is also the orientation of the strain ellipsoid and strain quadric representations of the strain.

The current version adds different orientations for the choice of Cartesian axes, and calculates four different strain tensors: Eulerian and Lagrangian, both as infinitesimal or finite strains. The strain definition that the program will use can be chosen on the GUI.

Earlier versions of this program were developed from the strain program of Ohashi, previously published in the book Comparative Crystal Chemistry by Hazen and Finger. Win Strain Version 4 is new code with a more robust solution to the eigenvalue problem of determining the orientation and values of the principal strains.

Download a zip archive that includes the program, the users guide and example datafiles. Then extract the pdf file of the manual which contains further installation instructions.

If you download and use the Strain program, please register with us by e-mail, so that we can inform you of new releases and updates of the software.

Last Update: Version 4.11 (November 2011). If you are using an older version, please update to this version.